Technical Mpi Sei overheating

[nsr500rossi]

Hi

I have a Abarth MPI Seicento

I noticed that the fans seems to be on rather a lot, seems to be on all the time in fact, maybe not when i first start the car, but as soon as it warms up, it seems to stay on.

Also, i am not getting any warm air from the foot heater vents, windscreen is ok, not brilliant, same for the face vents.

Looking inside the expansion bottle, the water looks light brown, i have a brown slime on the cap.

The engine temp light came on for the first time the other day, it does not come on around town, but i took the car on the duel carriageway and after 8 miles the light came on, i stopped and let it cool, then managed to get home without it coming on again (only 3 miles)

To add, i have only had this car for a couple of weeks.

I think it is losing some water..

If i feel the lower radiator hose, it seems cold, or luke warm after some driving, the upper hose gets warm as do the 2 hoses that go into the heater matrix.

I have looked through lots of overheating threads, but wanted to ask your advice.

I am hoping kit is not the head gasket!! could it be blocked radiator, thermostat stuck etc

Thanks
Mike

 

[fingers99]

Bleed the system. Test the thermostat. Check for leaks -- most likely hidden ones (often only seen once the car is up to temperature, engine running) are from the water pump itself and the water pump/water rail O ring. But I'd suspect that the HG may have gone by now. Compression test will reveal all.

 

[cc1]

Thermostat could be jammed shut.

 

[nsr500rossi]

Thanks for the replies.

Just had a quick look under the bonnet, after a drive.

I can see a white powder like substance on the the place where the top hose goes into the engine, so the water pump i guess, no sign of a leak but looks like it has been leaking.

I also have an oil leak, from under the same place, looks like from the head gasket!

Lower rad hose is still stone cold!

Mike

 

[rallycinq]

Lower hose should be pretty cold, thats where the cooled water comes from.

Upper hose goes into thermostat housing on gearbag end of engine.

Water pump is under cambelt cover, its driven by the cam belt.

Did you bleed the system?

What is the state of the coolant?

Does the top hose remain cold and then get hot all of a sudden?

Cheers

D

 

[nsr500rossi]

Lower hose should be pretty cold, thats where the cooled water comes from.

Ok thats fine then .

Upper hose goes into thermostat housing on gearbag end of engine.

Water pump is under cambelt cover, its driven by the cam belt.

Is that on the right hand side then?

Did you bleed the system?

Had a go at bleeding the other day, both hose at the bulkhead and the one by the expansion tank..

What is the state of the coolant?

coolant is a dirty light brown colour, i have lost about2.5 inches of water in the expansion tank in the last 50 miles

Does the top hose remain cold and then get hot all of a sudden?

Not sure about this one, i will check tomorrow, should i just run the car in the driveway and keep checking?

Cheers

Thanks

M

 

[rallycinq]

Looking into the engine bay from the front of the car, the cambelt, and therefore water pump are to the left, the gearbag and therefore the thermostat housing are to the right.

Top up the coolant with the bleed valves open until there is no more air in the system.

Run the car up from cold, idling in the driveway is fine, although it will take a while, you can use your hand on the throttle spindle to increase the revs away from idle whilst keeping the other hand on the water pipe coming from the thermostat.

You may get a little convected heat from the hot water in the head but you should suddenly feel a rise in temp when the thermostat opens.

Cheers

D

 

[nsr500rossi]

Ok thanks D, will do that tomorrow and report back

Car also needs a new clutch, annoying thing is ..our previous sei had both clutch and head gasket done 2 months before some prat pulled out in front of us ..car was write off ..ggrrrrrrrr

What do you think about a slight oil leak from what looks like the front right head to block?

Cheers

M

 

[rallycinq]

How much oil are you using between weekly checks?

Cheers

D

 

[nsr500rossi]

Hmmmm not checked, when we bought the car the oil did look good, then again seller said he had just changed the oil ..maybe to hide something!!!

I will check that as well tomorrow.

It does not seem to be leaking much, there is a small amount from the cam cover, this is on the front right corner as well, at first i thought that the oil showing around the head gasket was just the cam cover oil leak running down, maybe it is but not sure, there is a layer of oil on the gearbox ..not sure how long that has been accumulating for.

Maybe i will stay the oil with gunk then see how much build up also how much i am losing

M

 

[nsr500rossi]

Ok D

I ran the car with both bleed valves open and heating blowers on full, kept topping up the water as it drained, seemed that there was no air in system, no bubbles appeared.

next, put both bleed cap and expansion tank cap back on, left car ticking over for 10-15 mins with heating of and checked temp of the upper hose.

There was no sudden temp rise in the hose, what happened was the hose very slowly rose in temp staring from the engine (thermostat) and traveled down towards radiator ..here is the thing, it only got hot to 8 inches from the radiator, near the rad it was stone cold!

Also i can hear a water sound from the front of the car ..maybe radiator.

Does this all mean the thermostat is opening but the water can't get through the radiator, because it is blocked??

There does not seem to be any water leaking

Also, you can see residue of brown water ..dried on the exhaust manifold and over the expansion tank, so looks like it has overheated and blown from the tank previously.

Where is the water temp sensor on m the MPI ..will it be reading from the engine or radiator.

The fan did not seem to come on during my 15 mins of running the engine

Whats your diagnosis

Many thanks

Mike

 

[arc]

Theremostat is stuck closed. They can jam after overheating. This ties in with the signs of a previous overheat. That top hose should get suddenly warm as the stat opens. This is not happening, and the transfer of heat you are feeling is just heat being conducted through the coolant in the pipe - there is no coolant flow there.

Temperature probe is on the back of the head, gearbox end - sticking out next to the inlet manifold. Green plug iirc.

 

[nsr500rossi]

Brilliant, it makes sense now, i have ordered a new thermostat, will do the job tomorrow.

Think its best to flush the system at the same time as it looks pretty brown and gunky, can you recommend an decent engine flush?

`Thanks

Mike

 

[fingers99]

They're all reasonable, none are drop dead wonderful. Anything your local factor have.

 

[nsr500rossi]

Update.

Decided to clean the oil from under the thermostat housing hg area, sprayed with gunk then washed with a little water.

Thought i would drive round the block, check for oil ..only 500 yards.

Card is now hesitating at very low revs ..it chugs, above say 1200rpm it is fine, car is not jerking, but if i touch the throttle it miss fires a bit.

Also i got a flashing temp light, before, when it overheated, the temp light was on permanently.

What has caused this?

Thanks

M

 

[fingers99]

I've never seen a flashing temp light.

Best guess, HG has now gone. But compression test will reveal all.

 

[nsr500rossi]

Oh dear ...

Will get a compression tester tomorrow

What is the procedure for using a compression tester..

Cheers

Mike

 

[fingers99]

Lots of stuff on the web, but:

Charge battery overnight
Acquire an attractive helper.
Remove all plugs, disconnect TDC sensor (generally, at the connector on the bracket near the inlet mani. Check with aid of attractive helper that you have disconnected (no spark at plug will do).

Fit compression tester to #1 cylinder. Get attractive helper to hold the throttle fully opn while turning the engine over on the starter. Say 10 times or so.

Note down reading.

Repeat for all cylinders.

 

[nsr500rossi]

Ok thanks ..will update you tomorrow with result that will no doubt say i need a new head gasket gggrrrrrrrrr!

M

 

[nsr500rossi]

Ok, so i used radflush 2 part and cleaned system out, not as much gunk came out as i thought would.

Replaced faulty thermostat

Filled with reverse osmosis water (i keep a reef marine tank) and anti-freeze.

Car seems fine now, no overheating.

I have a couple of very small leaks from the bottom of the radiator, can just see a little vapour coming out, but don't seem to be losing water in a big way, will get a new rad soon though.

Bought a compression tester, but have not used it yet, will test compression in the next few days.

Getting more heat from the heaters, better but still not great from the lower vent.

And ... i have no control over the tempreture, maybe the control wire has come off ..??

Anyway, thanks for all advice

Clutch next ...gulp

Mike